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arXiv · 2609.19800

Spontaneous filament formation and network self-assembly via active phase separation

Elena Lucas·Varun Venkatesh·Amin Doostmohammadi
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Abstract

We introduce Active Model H$^{-}$, a scalar phase-field model of non-equilibrium phase separation in the overdamped hydrodynamic limit, and show that it produces filamentous networks with enhanced connections and arrested coarsening, a morphology not observed in existing scalar active field theories. Isolated filaments are unstable to spontaneous bending, and the resulting curvature drives self-propulsion towards the convex side, causing them to collide and assemble into a percolating network. The networks are locally non-equilibrium, with anomalously curved edges, disordered vertex angles and heterogeneous topological charge, yet recover Lewis's law macroscopically. Under noise they show balanced break and reform dynamics.

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Elena Lucas, Varun Venkatesh, Amin Doostmohammadi. 2026-09-17. Spontaneous filament formation and network self-assembly via active phase separation. https://arxiv.org/abs/2609.19800

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